Although traditionally columns have been installed in a central reservation, an opposite installation with columns behind the hard shoulder can improve maintenance operations and reduce traffic disruption when in process.
As glare becomes a major concern an optimised designed optic and/or the use of flat glass enclosures are necessary.
Key luminaires:
Main Roads - Points of note are;
The main usage of the road is for vehicles at high speed (>60km/h) but pedestrians, cyclists or slow vehicles may also be present on footpaths, cycle paths and slow lanes. Intersections can be present and need special attention.
A common installation is using columns around 10m high and in an opposite or twin central configuration but it needs to always be related to the road layout, the number of lanes involved and the lighting criteria to achieve.
Where cycle and pedestrian pathways are present the use of luminaires with different lamp settings is beneficial to comply with requirements for the road and also to be able to correctly light the pathways without needing to change the pole characteristics.
As in all road lighting applications a high IP rating has to be considered to extend maintenance periods.
Key luminaires:
Ring roads and radial roads - Points of note are;
These are usually medium speed roads and high-speed urban roads where pedestrians and cyclists are common.
Luminaire mounting heights around 8 and 10m in a staggered or single sided arrangement are usual, although many other possibilities can be considered due to the multiple layouts of these roads.
As these roads can be of multiple lanes the main concern is the common use by cyclist and pedestrians usage.
In some cases, when a road has many lanes and cycle and/or pedestrian pathways are also present the use of twin poles may be considered (i.e.
using an additional luminaire at a separate mounting height to light the adjacent pathways) or alternatively the use of bollards which also provide a physical separation between traffic types. In these cases using different light sources for motorised and other traffic (such as high pressure sodium and a white light lamp) can help to differentiate between the two areas.
Key luminaires:
Mixed traffic roads - Points of note are;
These are normally medium to low speed roads with a large number of slow vehicles and pedestrians. Intersections are very common. Regional roads and urban roads are mainly part of this group as well as commercial streets.
Columns no higher than 8m are commonly used in a single sided or staggered layout, although in some commercial streets with wide footpaths an additional column and luminaire may be used to achieve high quality lighting and differentiate areas.
For regional roads low luminance classes should be applied and illuminance classes where pedestrian usage is relevant.
Key luminaires:
Road lighting
Residential and local roads - Points of note are;
These roads are normally used by low speed mixed traffic. Pedestrian areas and local and residential roads are mainly part of this group.
Low mounting heights are common, with column height usually under 6m.
Single sided layouts may be used to reduce installation costs although layouts may vary due to multiple access points to private car parks or properties. The use of staggered layouts is common when parking lanes and wide footpaths are present.
Lighting classes tend to be from lower categories and in residential areas the use of high colour rendering lamps to improve perception is recommended.
In applications where crime ratios are high and facial recognition is required vertical and semi-cylindrical illuminance classes should be applied.
Low glare luminaires should be considered to reduce light trespass onto adjacent residential housing. Additionally the location and the orientation of the luminaires can help avoid any light trespass into houses.
Key luminaires:
Conflict areas and junctions - Points of note are;
In these areas traffic, either motorised or pedestrian, converges from many directions. Lighting in these areas has to increase awareness and guidance to drivers and pedestrians regarding the geometry of the area and the position of other users.
In terms of lighting the highest applicable class should be used in these areas, using the highest class of the incoming roads.
Road lighting
Access and exit lanes should be highlighted, including a short section of these lanes away from the conflict area. This is to ensure any obstacle in these areas is visible.
When positioning the luminaires the main aim is to help the incoming vehicles visibility. When entering a junction from a minor road a luminaire should be positioned to make vehicles visible as they approach the conflict area.
Columns can play a major role not only in terms of providing lighting but also to give guidance to the geometry of the area. A common technique is to increase the height of the columns in the conflict area and on the approaches.
On roundabouts columns placed in a single sided configuration around the outer part of a curve provide a clear guidance for a driver as they approach the area.
Key luminaires:
Schemes
Traffic
Scheme: Traffic route, 3 lanes, opposite arrangement. Total width 10.95m Luminaire(s) used: Triumph 1 150W HST, 10m mounting height, 36m spacing, 5° tilt Road: Lav = 5.75 cd/m² ; Emin/Eav = 0.59;
Threshold increment = 2%
Road lighting
Lighting columns and fixtures may be themed to blend into and complement the area they are situated within. Careful choice of column height is necessary to prevent lighting becoming excessively visible and detracting from the view.
However, a column height that is too low will reduce installation performance and require additional lanterns.
Whenever designing an installation the impact of the lighting hardware on a scene during daylight hours should be considered, as well as the performance of the lighting during darkness.
Catenary lighting solutions in which the lanterns are suspended along the centre of the carriageway are popular in many countries and remove the need for lighting columns and brackets. This can create a less cluttered environment at street level, although in architecturally interesting areas thought should be given as to the effect of the additional cabling on the field of view.
Frequently lighting columns collect additional street furniture, such as banners or signage. Lighting columns are constructed to withstand a defined windage (that is the force of the wind on the column). Windage is directly related to the surface area of any furniture mounted on or fixed to the column, and therefore adding additional objects to the column will increase the windage loading, and may cause weakening of the column and structural failure.
Techniques
General
Amenity lighting provides the essential lighting for the city or town shopping centres, residential streets, cycle paths, pedestrian crossings, precincts, town squares, parks, car parks both indoor and outdoor, underpasses and general security lighting. The mix of slow moving vehicles and pedestrians creates a challenge and the main emphasis is towards pedestrians, reducing accidents and helping prevent crime and the fear of crime.
Lighting can fulfil both functional and decorative elements by providing sufficient lighting to provide orientation and direction with security after dark. Good amenity lighting can provide guidance through city or town areas by the use of themed lighting, whether by using styled lighting equipment or by the use of different colour appearance light sources to provide aesthetic interest.
Operating costs and environmental impact are important and the use of photocells to reduce the number of hours the lighting is used can be very economical. Lighting control systems can provide even further savings by allowing switching or dimming of lamps at of-peak or night time situations.
Feeder Roads - Points of note are;
The risk of accidents is much greater on feeder roads from the high volume and speed of vehicles, particularly where children, elderly, partially sighted and handicapped pedestrians are present. Correctly designed lighting systems however will help drivers and pedestrians recognise potentially dangerous situations and will also help reduce crime against people, vehicles and property.
Feeder Roads generally use asymmetric light distribution street lanterns on 8–10m columns with outreach arms to position the lantern in the optimum location for road geometry. Alternatively lanterns can be post top mounted (without the outreach arm) but the lanterns will need the ability to re-direct the lantern peak intensity (typically using an adjustable lampholder) into road centre to improve efficiency and reduce installation and running costs.
For dual carriageway installations lanterns mounted back to back on centrally mounted lighting columns provide good economy and lighting efficiency.
White light sources – Metal halide, compact fluorescent and induction lamps provide good colour rendering conditions for drivers and pedestrians, improving visual perception and helping to provide early warning of impending situations. High-pressure sodium light sources are more efficient but suffer from poorer colour rendering characteristics.
Vandalism should not be a problem to lanterns mounted at 8-10m but in extreme cases polycarbonate bowls might be required.
Key luminaires:
Local and residential roads - Points of note are;
For local and residential roads post top lanterns on 5-8m poles with a symmetric or asymmetric distribution will help provide good vertical illuminance. Light above the horizontal should be avoided to reduce sky glow, improve efficiency and create less glare to drivers and residents.
Narrow pavements may need lanterns mounted using wall brackets.
Lanterns can be themed or styled to suit neighbourhood road and architectural layout. Strongly themed lanterns may require a lower mounting height 4-5m.
White light sources provide good colour rendering conditions for drivers and pedestrians improving visual perception and helping to provide early warning of impending situations.
Vandal and impact resistant luminaires may be required using polycarbonate.
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